Samsung Galaxy S3 — S3 been in water

I have a S3 that went into a bucket of water, dried it out as soon as possible and left it in a box of rice for 4 days, when I switched it back on the display worked ok but its asking to insert the sim card when it was already inserted, I thought it was the sim card slot so I replaced the combined sim card/micro sd card section, but its exactly the same, is there anything else to check??

I have a S3 that went into a bucket of water, dried it out as soon as possible and left it in a box of rice for 4 days, when I switched it back on the display worked ok but its asking to insert the sim card when it was already inserted, I thought it was the sim card slot so I replaced the combined sim card/micro sd card section, but its exactly the same, is there anything else to check??

Wrong...wrong...wrong...mistake after mistake ... - from the beginning to the end.

You'd have to submerged it immediately in at least 95 % alcohol for 2-3 seconds.Alcohol must penetrate entire interior of the phone ( 98% "Spirytus"- Product of Poland is the best). Let it dry in worm place for about 1 hour. And any device must work. - No exceptions, - unless it was damaged in the first moment from contact with water. Don't forget.. - don't waste the alcohol you've been using , it's still drinkable and good for your health.